Crews in hazmat suits spray foam on a damaged chemical tank in Garden Grove, Orange County. The tank was struck by a construction backhoe, triggering a massive evacuation. (Global 1 News)

GARDEN GROVE, Calif. — A massive chemical tank damaged by a construction backhoe forced the evacuation of more than 45,000 people from a densely populated area of Orange County on Sunday, as firefighters and hazmat teams worked to stabilize a potentially catastrophic explosion.

The incident occurred at approximately 9:15 a.m. at the Garden Grove Chemical Supply Co. facility on the 12000 block of Industry Drive, near the intersection of Garden Grove Boulevard and Euclid Street. Authorities said a construction crew accidentally struck a 50,000-gallon tank containing methyl ethyl ketone peroxide — a highly volatile industrial chemical used in plastics manufacturing.

"This is an extremely dangerous situation," said Garden Grove Fire Chief Maria Torres during a press briefing Sunday afternoon. "We have a crack in the tank that is allowing the chemical to vent slowly. That crack is actually reducing the immediate risk of a massive explosion, but it also means we are dealing with a continuous release of hazardous vapor."

Evacuation Under Way

The slow leak has prevented a pressure buildup that could have triggered a blast, but officials warned the chemical remains highly flammable and toxic. The evacuation zone extends roughly two miles in all directions from the facility, affecting homes, businesses, and several schools that were closed for the holiday weekend.

Residents flee the evacuation zone in Garden Grove as authorities warn of potential chemical explosion. Orange County sheriff deputies set up roadblocks across the suburban neighborhood. (Global 1 News)

Orange County Fire Authority hazmat crews established a 1,000-foot hot zone and deployed air monitoring equipment. No injuries have been reported.

"Our priority is to keep people away until we can safely transfer the remaining chemical to a secure container," said Torres. "That operation is expected to take at least 24 to 36 hours."

The construction backhoe that struck the tank was part of a routine site expansion project. The operator was not injured and is cooperating with investigators.

"We are deeply sorry for this incident," said a spokesperson for the construction firm, who declined to be named. "We are working with all authorities to ensure safety."

Residents were directed to evacuation centers at the Garden Grove Community Center and Bolsa Grande High School. Traffic on the 405 Freeway near the scene was partially shut down, causing gridlock across central Orange County.

"I heard a loud bang, then sirens everywhere," said resident Linda Nguyen, 52, who fled her apartment on Westminster Avenue with her two children. "We grabbed our phones and our dog. That's it. They told us we might not be back for days."

What Happens Next

Crews will attempt to pump the remaining chemical into a specialized tanker truck once the crack is stabilized. The operation requires precise temperature control and constant monitoring for vapor ignition. Air quality tests are ongoing.

"This is a textbook hazmat response," said Dr. Kevin Ross, a chemical safety expert at the University of California, Irvine. "The slow leak is actually a blessing in disguise. A rapid rupture would have been catastrophic. But they are not out of the woods yet. Any spark could still ignite the vapor cloud."

Authorities said the evacuation order will remain in effect until the tank is fully drained and the area is declared safe. Updates will be provided hourly via the city's emergency alert system.

— Jessica Ali, Global 1 News | Published May 24, 2026